To fertilize berries, test the soil beforehand to make sure the pH and nutrient mix is correct. Blueberries thrive in acidic soil with a pH between 4.09 and 5, and they are sensitive to over-fertilization. When the soil is adjusted to a lower pH, use high-acid fertilizers that contain ammonium nitrate, ammonium sulfate or sulfur-coated urea.Continue Reading
Fertilizers that contain nitrates such as calcium nitrate or chloride are lethal to some blueberry plants. Use high-nitrogen fertilizers instead.
Rhododendron and azalea fertilizer formulations work well with blueberries. Use 2 tablespoons of fertilizer for new plants. After the first year, calculate the amount of fertilizer based on the years planted. Use 1 ounce for each year planted, but never go over 8 ounces per plant.
Organic fertilizers are also effective. Blood meal or fish meal provide nitrogen. Bone meal and powdered seaweed provide phosphorus and potassium. Sphagnum peat or coffee grounds provide acidity.
Use appropriate blueberry fertilizer in case of iron or magnesium deficiencies. Iron deficiency manifests as yellow leaves with green veins, and magnesium deficiency manifests as reddish-yellow patches near the edges of the leaves.
Fertilize blueberries only once a year in the spring before the leaves grow to allow the fertilizer to penetrate the soil and reach the roots first.Learn more about Gardening & Landscapes